Seems like things can be objectively "better" or "worse" in terms of fulfilling specific utilitarian functions. A DVD player with reliable performance is preferable to a player that always skips, glitches, etc. A sharp knife is objectively better for cutting through a loaf of bread than a dull knife.

But music is subjective because it is art. Even though the artist creates with a specific aesthetic goal in mind, works of art are always open to individual emotional reaction and interpretation, and thus remain subjective. But the ultimate subjectivity doesn't mean that we can't talk about it. People generally have reasons for their opinions beyond "I like it" or "I don't like it", and these reasons can be discussed. In so far as people share similar aesthetic values, consensus can be reached. Otherwise there is unbridgeable disagreement.

.No I don't care about your faggy Sufjan Stevens. No I don't know the difference between death metal and black metal. No I don't give a shit about punk rock, besides isn't punk rock an antiquated and fossilized cultural piece? Like feminism and kwanzaa?